title: Biochemical characterization of Acacia schweinfurthii serine proteinase inhibitor.
abstract: One of the many control mechanisms of serine proteinases is their specific inhibition by protein proteinase inhibitors. An extract of Acacia schweinfurthii was screened for potential serine proteinase inhibition. It was successfully purified to homogeneity by precipitating with 80% (v/v) acetone and sequential chromatographic steps, including ion-exchange, affinity purification and reversed-phase high performance liquid chromatography. Reducing sodium dodecyl sulphate polyacrylamide gel electrophoresis conditions revealed an inhibitor (ASTI) consisting of two polypeptide chains A and B of approximate molecular weights of 16 and 10 kDa, respectively, and under non-reducing conditions, 26 kDa was observed. The inhibitor was shown to inhibit bovine trypsin (Ki of 3.45 nM) at an approximate molar ratio of inhibitor:trypsin (1:1). The A- and B-chains revealed complete sequences of 140 and 40 amino acid residues, respectively. Sequence similarity (70%) was reported between ASTI A-chain and ACTI A-chain (Acacia confusa) using ClustalW. The B-chain produced a 76% sequence similarity between ASTI and Leucaena leucocephala trypsin inhibitor.
authors.affiliation: Department of Biochemistry & Microbiology and.
authors.forename: Frank
authors.initials: F
authors.lastname: Odei-Addo
authors.forename: Carminita
authors.initials: C
authors.lastname: Frost
authors.forename: Nanette
authors.initials: N
authors.lastname: Smith
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Ogawa
authors.forename: Koji
authors.initials: K
authors.lastname: Muramoto
authors.forename: Maria Luiza Vilela
authors.initials: ML
authors.lastname: Oliva
authors.forename: László
authors.initials: L
authors.lastname: Gráf
authors.forename: Ryno
authors.initials: R
authors.lastname: Naude
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D004305:Dose-Response Relationship, Drug; D007887:Fabaceae / Q000737:chemistry*; D008969:Molecular Sequence Data; D010802:Phylogeny; D012639:Seeds / Q000737:chemistry; D016415:Sequence Alignment; D057057:Serine Proteases / Q000378:metabolism*; D015842:Serine Proteinase Inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D013329:Structure-Activity Relationship
chemical_list: D015842:Serine Proteinase Inhibitors; D057057:Serine Proteases
keywords: Acacia schweinfurthii; amino acid sequence; proteinase inhibitors; trypsin inhibitor